Related Field
The present invention relates to a powder pre processing method for additive manufacturing according to the preamble of claim 1.
Description of Related Art
Freeform fabrication or additive manufacturing is a method for forming three-dimensional articles through successive fusion of chosen parts of powder layers applied to a worktable.
An additive manufacturing apparatus may comprise a work table on which said three-dimensional article is to be formed, a powder dispenser, arranged to lay down a thin layer of powder on the work table for the formation of a powder bed, an energy beam for delivering energy to the powder whereby fusion of the powder takes place, elements for control of the energy given off by the energy beam over said powder bed for the formation of a cross section of said three-dimensional article through fusion of parts of said powder bed, and a controlling computer, in which information is stored concerning consecutive cross sections of the three-dimensional article. A three-dimensional article is formed through consecutive fusions of consecutively formed cross sections of powder layers, successively laid down by the powder dispenser.
In additive manufacturing it is important to control the powder distribution. It is desirably to distribute a predefined amount of powder over a predetermined area. This requires a well defined method and apparatus for repeatedly removing a predetermined amount of powder from a powder storage to a powder distributor device. One problem that may arise is that the powder may have more or less of built in moisture. Said moisture may affect the flowability of the powder which in turn may affect the smoothness and thickness of the applied powder layer on the work table. Moisture in powder material for additive manufacturing may also affect the material properties of the final 3-dimensional product in an undesirable way.